Hearing benefits of second-side cochlear implantation in two groups of children.

Objective: To investigate the additional bilateral benefits of a second cochlear implant (CI) in a group of young children (<6 years of age) and a group of older children (>6 years of age).

Method: This is a Belgian tertiary multi-centre study in which 33 CI-children with a second implant between the age of 2 and 12 participated. Assessments took place pre-second implant and at several time intervals post-fitting on pure tone audiometry and speech recognition in quiet and noise (+10 dBSNR). Testing was done with the first and second implant alone and bilaterally. Results were analysed separately for children younger and older than 6 years at the time of implantation of the 2nd CI.

Results: After 18 months of bilateral implant use all children obtained significantly higher hearing thresholds in the bilateral condition in comparison to both the unilateral conditions (p(CI1)=0.035/p(CI2)=0.042 for the younger children and p(CI1)=0.021/p(CI2)=0.007 for the older children). The speech recognition scores in quiet were for all children superior in the bilateral condition (p(CI2)=0.011 for the younger children and p(CI1)=0.016/p(CI2)=0.003 for the older children). In the noisy condition only significant bilateral better results were obtained in the group of younger children (p(CI1)=0.028/p(CI2)=0.034).

Conclusions: Bilateral cochlear implantation offers advantages to all children. Even for the children who received a second implant after the age of 6 a progress is determined after 18 months. However, the data appear to show a beneficial performance for those children who received their second implant before the age of 6, especially in the more challenging conditions.